The present invention relates generally to bellows, specifically to vented bellows, and particularly to pneumatic system bellows and their method of manufacture.
It is often desirable to remotely control an electrical system utilizing air pressure to reduce the possibility of sparks and/or electrocution. As an example, such control systems may be utilized in high pressure washers where water is pressurized for spraying upon surfaces desired to be cleaned. So as to prevent unintentional pressurization of the pneumatic system due to changes in temperature or atmospheric pressure, such systems are normally vented to the atmosphere. Thus, a need has arisen for vented bellows which are particularly advantageous for use in control systems which are of a simple design including few parts which are simple and economical to manufacture and assemble and which include provisions for selectively sealing the vent to the atmosphere. Similarly, a need has arisen for pneumatic systems for other applications which are of a simple design including few parts which are simple and economical to manufacture and assemble.
The present invention solves this and other needs in the design of pneumatic systems by providing, in the preferred form, a valve tube loosely received on a vent hole tube having a vent hole located intermediate the ends of the valve tube. The member which compresses the bellows of the pneumatic system also compresses the valve tube to seal the vent hole.
In another aspect of the present invention, an integral pneumatic system formed of homogeneous material is provided including bellows located intermediate first and second tubes. The bellows have a generally rectangular cross section and include a flat top and bottom add accordion sides having longitudinal fold lines which are generally parallel to the first and second tubes.
Additionally, in still another aspect of the present invention, th pneumatic system is blow molded in first and second mold halves having a bellows cavity located intermediate first and second tube cavities. The free end of the first tube is sealed and the blow is introduced into the free end of the second tube. The bellows cavity is generally trapezoidal in cross section defining major longitudinal undercuts.
Thus, it is an object of the present invention to provide a novel pneumatic system.
It is further an object of the present invention to provide such a novel pneumatic system of a simple design.
It is further an object of the present invention to provide such a novel pneumatic system including few parts.
It is further an object of the present invention to provide such a novel pneumatic system which is simple and economical to manufacture and assemble.
It is further an object of the present invention to provide such a novel pneumatic system having a two-stage actuation for closing a vent hole and then compressing a bellows.
It is further an object of the present invention to provide such a novel pneumatic system including a novel vent hole sealing structure.
It is further an object of the present invention to provide such a novel pneumatic system where the vent hole sealing structure biases the member which compresses the bellows.
It is further an object of the present invention to provide such a novel pneumatic system which is integrally formed of homogeneous material.
It is further an object of the present invention to provide such a novel pneumatic system having bellows including longitudinal fold lines.
It is further an object of the present invention to provide such a novel pneumatic system having bellows including longitudinal fold lines generally parallel to the mold part line.
It is further an object of the present invention to provide such a novel pneumatic system which may be blow molded.
These and further objects and advantages of the present invention will become clearer in light of the following detailed description of an illustrative embodiment of this invention described in connection with the drawings.